Today I was trying to compile a module using an extension in C and
noticed there are differences between compiling it on Python 2.5 and 2.6.
I was trying to compile psutil (svn checkout
http://psutil.googlecode.com/svn/trunk/ psutil) but I think that the
problem may occur with any other package using C extensions.

Python 2.5:

D:\pyftpdlib\svn\psutil\trunk>C:\python25\python.exe setup.py install
running install
running build
running build_ext
error: Python was built with Visual Studio 2003;
extensions must be built with a compiler than can generate compatible
binaries.
Visual Studio 2003 was not found on this system. If you have Cygwin
installed,
you can try compiling with MingW32, by passing "-c mingw32" to setup.py.



Python 2.6:

D:\pyftpdlib\svn\psutil\trunk>C:\python26\python.exe setup.py install
running install
running build
running build_ext
building 'psutil/_psutil_mswindows' extension
error: None

What is the specific error you are reporting?

Currently I haven't any C compiler installed on my system so I expect
distutils to report that every time I try to compile a C module extension.
Python 2.5 did that while Python 2.6 does not.

The problem has two causes:
- IOError is raised when no compiler is found. DistutilsPlatformError
should be used instead, this was fixed by #4702.

- the distutils.util.grok_environment_error function transforms a
IOError("Unable to find vcvarsall.bat") into "error: None".

This function should not be used IMO. Its docstring claims that it
"Handles Python 1.5.1 and 1.5.2 styles", but str() does a better job...

Patch attached.

Tarek: This patch seems reasonable to me, is this something that can be applied?

I guess i can be applied on distutils, and backported in distutils2. I'll do it in the coming days.

Notice that I am now applying only bug fixes and regression fixes now for distutils.

I will commit this if Tarek does not do it shortly.

In distutils2, I’ll remove grok_environment_error wholly, since it exists for 1.5 compat only.

Giampaolo, can you test Amaury’s patch?  I’d prefer some testing before committing.

I don't have the same setup I had at the time when I submitted the first message so maybe something has changed in meantime.
Below is what I get on Windows 2000 SP-3, no VS installed, python 2.7, before and after the patch.

C:\Documents and Settings\foo\Desktop\psutil>setup.py build
running build
running build_py
copying psutil\compat.py -> build\lib.win32-2.7\psutil
copying psutil\error.py -> build\lib.win32-2.7\psutil
copying psutil\_psbsd.py -> build\lib.win32-2.7\psutil
copying psutil\_pslinux.py -> build\lib.win32-2.7\psutil
copying psutil\_psmswindows.py -> build\lib.win32-2.7\psutil
copying psutil\_psosx.py -> build\lib.win32-2.7\psutil
copying psutil\_psposix.py -> build\lib.win32-2.7\psutil
copying psutil\__init__.py -> build\lib.win32-2.7\psutil
running build_ext
building '_psutil_mswindows' extension
error: Unable to find vcvarsall.bat


Although the message is improved ("Unable to find vcvarsall.bat" vs "None") it seems the patch had no effect.